1. Field of the Invention
The present invention relates to sterilization pouches for holding items during sterilization, and more particularly, to a sterilizable pouch having an improved means of sealing the pouch opening.
2. Description of the Prior Art
Sterilizable pouches are well known in the art. Hospital type pouches consist generally of a paper sheet which is permeable to gases but impermeable to microorganisms and an opposing transparent plastic sheet which is impermeable to gases and microorganisms. The paper and plastic sheets are typically heat sealed along three or four edges.
Lewis, U.S. Pat. No. 4,194,622 illustrates a sterilizable pouch which is sealed on all four edges. A slit adjacent one edge and between two side edges provides access to the interior of the pouch. An adhesive strip on the paper sheet between the slit and the one edge of the paper sheet is provided so that when folded over, it covers and seals the slit.
Sibrava et al., U.S. Pat. No. 4,276,982 discloses a sterilizable pouch which is sealed on three edges. An opening is defined between the fourth edge of the plastic sheet and a flap created by an extension of the paper sheet. An adhesive strip on the paper flap spaced from the opening provides a seal for the opening when the flap is folded over so that the adhesive strip contacts the opening and the plastic sheet. Alternatively, the adhesive strip can be placed on the plastic sheet adjacent to but spaced from the unsealed fourth edge. The paper flap is folded over the unsealed edge and pressed against the adhesive strip to provide the seal for the opening in the pouch.
It has been observed that pouches having foldable flaps to cover the opening suffer from poor alignment of the flap when affixing to the paper and plastic ends. Wrinkles in the seal provide air channels for the entry of microorganisms.
A commercially available sterilization pouch is heat sealed on each of its four edges. An opening is provided by a slit in the plastic sheet similar to that shown in Lewis, U.S. Pat. No. 4,194,622. A seal for the opening is provided by an adhesive backed paper strip connected to the plastic sheet adjacent to and spaced from the slit. A removable liner covers the adhesive side of the paper strip. When it is necessary to close the slit to seal the pouch, the liner is removed and the paper member pressed against the slit.
The pouches having an opening provided by a slit have been observed to limit the ease with which items can be placed into the pouch and frequently tear when the pouches are loaded.
An object of the present invention is to provide a sterilizable pouch which has an improved means of sealing the opening to avoid the creation of air channels. A further object of the present invention is to provide such a pouch with easy access to the opening so that tearing is avoided.